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Inexplicable vents on alpine summits #1114
Back To Discussion List Written: 2004.02.09 by: Paul Kubik

After reading Tom Tiedje's article on the vents of Alpen Mountain, we were next weekend on Mount Mulligan across Raffuse Creek to the west. On skiing down from the summit I skied right past a hole in the snow the diameter of two basketballs. On inspection, it revealed a snow cavern below it all the way to the bare ground- a drop of about 2.5 meters. The cavern area would have accommodated several people inside. I don't think it was a snow cave but rather created by warm air. There were no large trees nearby. On mentioning this to Jos van der Burg, he recalled seeing something similar southwest of Mountain Lake hut on a ridge crest. Has anyone any idea what causes these snow holes? My best guess is some kind of geothermal source. Some others have said there were some in a valley east of Cypress Peak near Mount Fee. I investigated these about 20 years ago and couldn't be convinced for sure they were caused by heat.


#287 - 2004.04.12 Frank W. Baumann - Mt. Mulligan volanics
There is an interesting occurrence of columnar basalt on the north side of Mt. Mulligan along a deactivated logging road at about 1100 metres elevation. I would guess these are Holocene less than 10000 years old) volcanics, but don't know for sure.

Even more interesting is the massive slow moving rock failure northwest of Mt. Mulligan, just above the Stawamus River and immediately north of Ray Creek. The Vancouver Island Natural Gas pipeline goes through this slowly moving mass of rock that is marked by a very prominent set of arcuate scarps.

With regard to the original inquiry, is it possible the vent hole is related to an adit or shaft- there was a lot of mining in that area.

#240 - 2004.02.11 Paul Kubik - Cogburn quarry warm seep
The location of the warm seep is the rock quarry before the Charles branch. Last spring when I was up there, there was a clearing with a big smooth slab of very dark rock that they were breaking off blocks from. No one was around at that time. I forget the name of the operation, I'd have to go onto MINFILE but I believe it has an entry on that database. It's a very low flow rate and probably 100 degrees Fahrenheit or maybe a bit warmer. But definitely, it's warm.

#239 - 2004.02.11 Drew Brayshaw - Alpen/Mulligan geology
The online BCGS map

shows a small outcropping of Garibaldi group volcanics on the north slope of Mulligan. The remainder of the mountain maps as Gambier Group metamorphic rocks.

Paul, do you mean the quarry in upper Cogburn, a few km before the Charles Creek turnoff?

#238 - 2004.02.11 Glenn Woodsworth - Underlying volcanism?
Paul is correct that thermal springs are generally found in low-lying areas. But there are exceptions. For example, the Mist Mountain springs in Kananaskis are very high up on the peak. I am not aware of any young volcanic rocks on Alpen or Mulligan. Don't have the map handy, but I think volcanics there are all older (Cretaceous, probably same age as Sky Pilot stuff). A check of the area during summer would be worthwhile. And Drew's explanation is also worth consideration.

#237 - 2004.02.11 Paul Kubik - Underlying vulcanism?
I'm not disagreeing with either of what Drew or Glenn has to say. I am surprised that a warm spot would occur on a mountain top (Mount Mulligan and Alpen Mountain) rather than a low point, which is where most, if not all, hot springs I am familiar with occur. The only thing that comes to mind is that there may be volcanic stocks that underlie Mulligan and Alpen and perhaps hot water or gas is seeping out through the top via fractures in the rock.

Incidently, I stopped by the rock quarry in Cogburn Creek (Harrison East area) and found a warm seep emerging from the base of the rock they are mining for slabs. I hadn't seen that one mentioned anywhere. Just wondering if Glenn was aware of that one.

#234 - 2004.02.10 Glenn Woodsworth - Geothermal?
Given that Mulligan is not that far from Ring Creek headwaters, or Garibaldi, for that matter, my guess is that there is a bit of low-grade geothermal heat there. Similar "warm" patches have been seen over the years in the Table Meadows area. No hot springs are known west of the lower Sqamish, but it doesn't mean that there can't be a bit of warm seepage. I've seen similar snow-free patches in the Terrace-Kitimat vally, north of the well known Lakelse hot springs.

#233 - 2004.02.10 Drew Brayshaw - Geothermal gradient
Generally speaking the temperature of the subsurface does not change much and increases with depth. A hot spring or steam vent is not necessary to melt snow... any vent opening on a cavern or set of voids would tend to melt snow by the process of exchanging cold air from the surface for warmer air below ground. You can see this process at work at the mouth of limestone cave systems or lava tubes in winter when there is snow on the ground.

I don't know that that necessarily explains the mystery snow vents but it is worth considering along with other factors.